design and analysis of the support structure …umpir.ump.edu.my/id/eprint/8407/1/cd8139.pdf ·...

DESIGN AND ANALYSIS OF THE SUPPORT STRUCTURE FOR AN OPEN

CHANNEL FLUME

NABIL FIKRI BIN ZUIFUL ZUBRI

Report submitted in partial fulfilment of the requirements for the award of

Bachelor of Mechanical Engineering

Faculty of Mechanical Engineering

UNIVERSITI MALAYSIA PAHANG

JUNE 2013

iv

STUDENT’S DECLARATION

I hereby declare that the work in this project is my own except for quotations and

summaries which have been duly acknowledged. The project has not been accepted

for any degree and is not concurrently submitted for award of other degree.

Signature :

Name : Nabil Fikri bin Zuiful Zubri

ID Number : MG 09018

Date : 21 JUNE 2013

vii

ABSTRACT

Open channel flumes which will be built on the ground level need a support structure

to minimize the displacement at the sidewall due to the hydrostatic and dynamic

pressure of water. The objectives of the study are to evaluate the pressure at the

sidewall of the flume, and to design a supports structure for the sidewall of the flume

under certain flow conditions. Three basic designs were selected and drawn using

Solidwork software and solved with the Autodesk Simulation Multiphysics solver.

From the data obtain it shows that Design 1 with 0.5 m breadth, 0.44 m length and 21

of support structure by using Ready Mix Concrete Normal Mix Grade 30 gave the

smallest value of wall displacement, and 81.73% effectiveness of the support

structure. Simulation result shown that the flume did need a support structure to

reduce the displacement of the sidewall. As a conclusion, Design 1 as it gave the

desirable result with the acceptable cost involved, effectiveness and economically.

viii

ABSTRAK

Saluran air terbuka yang akan dibina di atas paras tanah memerlukan struktur

sokongan untuk mengurangkan anjakan di sisi akibat tekanan hidrostatik dan

dinamik air. Objektif kajian ini adalah untuk menilai tekanan pada dinding sisi

saluran air, dan mereka bentuk struktur sokongan untuk sisi saluran air di bawah

keadaan aliran tertentu. Tiga reka bentuk asas telah dipilih dan direka menggunakan

perisian Solidwork dan diselesaikan dengan penyelesai Simulasi Multiphysics

Autodesk. Dari data yang diperolehi menunjukkan bahawa Reka Bentuk 1 dengan

0.5 m lebar, 0.44 m panjang dan 21 struktur sokongan dengan menggunakan Konkrit

Sedia Bancuh Bancuhan Biasa Gred 30 memberi nilai terkecil anjakan pada dinding,

dan keberkesanan 81.73% kepada struktur sokongan. Hasil simulasi menunjukkan

bahawa saluran air memerlukan struktur sokongan untuk mengurangkan anjakan sisi.

Kesimpulannya, Reka Bentuk 1 kerana ia memberikan hasil yang diingini dengan

melibatkan kos yang boleh diterima, keberkesanan dan dari segi ekonomi.

ix

TABLE OF CONTENTS

Page

EXAMINER’S DECLARATION ii

SUPERVISOR’S DECLARATION iii

STUDENT’S DECLARATION iv

DEDICATION v

ACKNOWLEDGEMENTS vi

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENTS ix

LIST OF TABLES xii

LIST OF FIGURES xiii

LIST OF SYMBOLS xv

LIST OF ABBREVIATIONS

xvi

CHAPTER 1 INTRODUCTION

1.1 Introduction 1

1.2 Background 1

1.3 Problem Statement 2

1.4 Objectives 2

1.5 Scope of Project

3

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 4

2.2 Open Water Channel Flow Flume 4

2.3 Counterfort Retaining Wall 6

2.4 Sliding Safety Factor 9

2.5 Fluid Structure Interaction Problem 10

2.6 Design Consideration for Counterfort wall 11

2.6.1 Breadth of Support Structure 13

x

3.5 Procedure 18

3.5.1 Breadth of Support Structure 18

3.5.2 Amount of Support Structure 19

3.5.3 Length of Support Structure 20

3.6 Actual Design 21

3.6.1 Water Channel without Support 21

3.6.2 Ghazavi Design, Design 1 & Design 2 22

3.6.3 CIDB Material List 24

3.8 Flow of the Project

25

CHAPTER 4 RESULTS AND DISCUSSION

4.1 Introduction 27

4.2 Flow Simulation 27

4.3 Breadth of Support Structure 28

4.4 Amount of Support Structure 29

4.5 Length of Support Structure 30

4.6 Discussion 31

4.6.1 Breadth of the support structure 31

4.6.2 Amount of the support structure 35

2.6.2 Amount of Support Structure 13

2.6.3 Length of Support Structure 13

CHAPTER 3 METHODOLOGY

3.1 Introduction 14

3.2 Computer Aided Design (CAD) 14

3.2.1 Solidwork 14

3.3 Finite Element Analysis (FEA) 15

3.3.1 Autodesk Simulation Multiphysics 15

3.3.2 Solidwork (Flow Simulation) 16

3.4 Conceptual Design 16

3.4.1 Dimension 17

3.4.2 Design 17

xi

4.6.3 Length of the support structure 40

4.6.4 Design Selection

44

CHAPTER 5 CONCLUSION AND RECOMMENDATIONS

5.1 Introduction 45

5.2 Conclusions 45

5.3 Recommendations

46

REFERENCES 47

APPENDICES

A Formula and Calculation 50

B Result of Simulation Autodesk Simulation

Multiphysics

52

C Gantt Chart For Final Year Project 1 61

D Gantt Chart For Final Year Project 2 62

xii

LIST OF TABLES

Table No. Page

2.1 Lower and upper bounds of designs variables 8

3.1 CIDB material list 25

4.1 Effect of breadth of the support structure 28

4.2 Effect of amount of support structure 29

4.3 Effect of length of support structure 30

4.4 Percentage of effectiveness of support structure 33

4.5 Volume of structure 34

4.6 Cost of material 34







xiii

LIST OF FIGURES

Figure No. Page

2.1 Schematic views of the swimming flume at Otago University 5

2.2 Water channel for Klang river in Kuala Lumpur 6

2.3 Water channel for drainage system 7

2.4 Water channel on a ground level without counterfort wall 7

2.5 Design variable for typical reinforced concrete counterfort retaining

walls

8

2.6 Static and transient uplift pressure 10

2.7 Geometry and finite element discretization of dam 11

2.8 Mass Concrete 12

3.1 Conceptual design of the open water channel flow flume 17

3.2 Side View-Example of changes of breadth of the support structure(a)

0.1m (b) 0.3m (c)0.5m

19

3.3 Side View-Example of changes of amount of the support structure (a)

six (b) eleven (c)twenty-one

20

3.4 Front view-Example of changes of length of the support structure (a)

0.22m (b)0.33m (c)0.44m

21

3.5 Water channel without support structure 21

3.6 Example of displacement of the water channel without support 22

3.7 Ghazavi design 23

3.8 Design 1 23

3.9 Design 2 24

3.10 Project’s flow chart 26

4.1 Graph of displacement of sidewall against breadth of support

structure

31

xiv

4.2 Graph of displacement of sidewall against the amount of support

structure

35

4.3 Graph of overall displacement against length of support structure 40

xv

LIST OF SYMBOLS

A Area

Pa Pressure

g Gravity

a Acceleration

F Force

l Length

n Number

V Volume

ρ Density

h height

% Percentage

m Meter

v velocity

xvi

LIST OF ABBREVIATIONS

2D 2 Dimensional

3D 3 Dimensional

CIDB Construction Industry Development Board Malaysia

FEA Finite Element Analysis

UMP University Malaysia Pahang

SSF Sliding Safety Factor

TNB Tenaga Nasional Berhad

1

CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

Renewable energy refers to the energy which comes from natural resources such

as sunlight, wind, rain, tides, and geothermal heat which is naturally replenished.

Renewable energy can be particularly suitable for developing countries. In the rural

areas, the transmission and distribution of energy generated from fossil fuels can be

difficult and expensive. Therefore by producing the renewable energy resources locally,

it can offer a viable alternative.

Renewable energy projects in many developing countries have shown that the

renewable energy can contribute directly to poverty alleviation by providing the energy

needed for creating businesses and employment. Through renewable energy also, it can

contribute to education by supplying electricity to schools.

1.2 BACKGROUND OF STUDY

In this modern era, vast amount of energy required to generate electricity. The

energy is used to power up machines, supplying electricity to the residential area, and to

move vehicle. Since the finding of fossil fuel, it’s being started to use it until now as

main source of energy. In Malaysia, in the early eighties, oil-fired generators were used

to produce electricity. As years passing by Tenaga Nasional Berhad (TNB) had found

alternative resources, and the oil requirement has reduced over the years. Most of the

2

time, fossil fuels were depends too much; therefore renewable energy resources must be

obtained. In this chapter, the problem statement, objective, hypothesis and scope of

study will be explain in detail.

1.3 PROBLEM STATEMENT

In rural and remote areas, it is always hard to supply the continuously stable

electricity to the population. A steady supply of fuel would be required to generate

electricity as generator was using fuel. This will be a problem in term of cost as

nowadays the price of fuel is increasing. Therefore, as an alternative, a micro-hydro

turbine will be installed to supply electricity in these areas.

Before an actual size of the mini-hydro turbine could be fabricated, a model scale

of micro-hydro turbine would be required to be built and tested. Therefore, a flume

needs to be developed in order to simulate the river flow, and test the turbine to find the

potential amount electricity to be generated, and the efficiency of the system.

The flume will be built on the ground; therefore, it has no support structure to

sustain the pressure of water at the wall. Hence, building the side support structure to

sustain the hydrostatic and dynamic pressure of the water and analysis of it will essential

to consider.

1.4 OBJECTIVE

The objectives of the study are:

i) To evaluate the pressure distribution at the sidewall of the flume.

ii) To design a support structure for the sidewall of the flume.

iii) To analyse the effect of support structure on the displacement of sidewall of the

flume.

3

1.5 SCOPE OF PROJECT

The scope of the study are:

i) To evaluate the pressure distribution at the sidewall of the flume.

ii) To perform a structural analysis upon the support structure.

iii) Run a simulation of static and dynamic pressure of water upon the flume wall.

iv) To analyse the possible three design of the flume support structure.

v) Concrete will be used as the material of support structure.

4

CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

This chapter includes the study of the water flume from various sources. In this

chapter also, the design for a support structure of the flume could be determined

2.2 OPEN WATER CHANNEL FLOW FLUME

In order to simulate the flow of a river, an open water channel flow flume need to

be build. The open water channel had been used in the Otago University for aquatic

research such as swimming. The swimmer will not move if he/she swim in the

swimming flume, as the water being pumped into the swimming flume. The amount of

water will be constant as the water move in a circulation flow. Therefore, thorough

research being done by Robbin Britton (1998) to keep the water flow stable. Besides

that, according to Robbin Britton (1998), the swimming flume can be used to test kayak

and canoe. In the upcoming research, this water channel could be used to simulate a lab

scale wave or tsunami.

5

Figure 2.1: Schematic views of the swimming flume at Otago University

Source: Britton (1998)

Figure 2.1 shows the schematic views of the swimming flume at the Otago

University. The test section of the swimming flume used by Otago University is

rectangular shape channel and material used is fiberglass, stainless steel and mild steel.

Even though, fiberglass has the advantage of lightweight and easy to install but the cost

is high. Therefore we have come to an option to choose concrete as our material in term

of cost.

In the early days, water channel were used to transport log from the cutting area

to the processing area. Now, the water channels are widely used in the drainage system

as shown in Figure 2.2. This will help to flush out the rain water during rain and prevent

flash flood in a larger city. For example in Kuala Lumpur, when it is raining a flash

flood always occur due to the poor drainage system, therefore the building of the open

water channel help the flow of rain water and preventing the flash during raining season.

6

Figure 2.2: Water channel for Klang River in Kuala Lumpur

Sources: HUME Concrete Marketing

2.3 COUNTERFORT RETAINING WALLS

The water channel will be place at the ground level. As being told before, the

water channel is similar to the drainage system which uses concrete as their main

material to build it. Figure 2.3 shows the drainage system and the outer sidewall of the

drain is being supported by the soil. Meanwhile in our case there will be no soil to

support the sidewall as shown in figure 2.4. As we know the pressure at the bottom of

the water channel will be the highest. Since the thickness of the wall of the water

channel is the same therefore a counterfort retaining wall had been considered in our

design to support the sidewall of the water channel.

7

Figure 2.3: Water channel for drainage system


Figure 2.4: Water channel on a ground level without counterfort wall


According to M. Ghazavi (2003), in his journal he stated that to design a

counterfort retaining wall there is some standard that must be followed to determine the

stem thickness, base thickness, distance between counterfort, counterfort thickness and

lengths of toe and heel. By following the method and parameter suggest by M. Ghazavi

as shown in table 2.5 we could determine the size and design of our counterfort retaining

wall. Table below shows the lower and upper bound of the design variables for the

counterfort walls

8

Figure 2.5: Design variable for typical reinforced concrete counterfort retaining walls

Source: Ghazavi (2003)

Table 2.1: Lower and upper bounds of design variables

Lower bound Upper bound

X1min=0.3H X1max=3H

X2min=H/10 X2max=H/8.5

X3min=H/10 X3max=H/8.5 X4min=20 cm X4max=30 cm X5min=0.1H X5max=2H X6min=0.1H X6max=H X7min=20 cm X7max= 50 cm X8min= 0.3H X8max= 0.7H X9min= minimum of shrinkage and

temperature rebar at heel in x direction X9max= maximum of shrinkage and

temperature rebar at heel in x direction X10min=minimum of shrinkage and

temperature rebar at heel in x direction

X10max= maximum of shrinkage and

temperature rebar at heel in x direction

X11min= minimum of shrinkage and

temperature rebar at heel in y direction







9


temperature rebar at toe in x direction








temperature rebar at toe in y direction








temperature rebar at stem in z direction








temperature rebar at stem in y direction







X21min= minimum of inclined rebar at

counterfort

X21max= maximum of inclined rebar at counterfort

X22min= minimum of shear rebar at

counterfort

X22max= maximum of shear rebar at

counterfort

Source: Ghazavi (2003)

With the parameter obtained from the research of M. Ghazavi (2003), not all of it

will be used in the study to design the support structure of the sidewall of the water

channel. With the useful information, we could design the counterfort easily and later we

could run a simulation to test the design whether the counterfort wall could sustain he

pressure from the water.

2.4 SLIDING SAFETY FACTOR

In Figure 2.6 show the front view of the water channel which is similar to

concept of a wall of a dam. Wall of a dam is thicker at the bottom compared at the

surface. This due to the concept of pressure, as we go deeper in the water, the pressure

will increase. Therefore, that’s why the wall is always thick at the bottom to sustain

pressure.

But even though, the bottom of the wall is thick, we should never neglect the

possible damage that might affect the design. One of the potential threats to the design is

10

crack. According to Farrokh Javanmardi (2004) whenever there is a crack at the inner of

dam, the pressure which comes from the water will push the water into the crack hence

making a new crack opening and filling the void. As this process continues, the crack

will be increasing and the length of crack is denoted as Lcr

Figure 2.6: Static and transient uplift pressure

Source: Javanmardi (2004)

Sliding Safety Factor (SSF) is the factor of safety against sliding on the sand

layer beneath the footing (J. Michael Duncan, 1999). From Farrokh Javanmardi research

he applied the SSF in his study to show the movement of the dam when there is a crack.

Therefore we could use this method to determine whether the wall of the retaining wall

will crack or not. The shape of the flume is U-shape, therefore is does not have a sand

layer footing as stated by Farrokh Javanmardi (2004) in his journal. Even though it does

not have a sand layer footing, but the method could be applied to this study

2.5 FLUID STRUCTURE INTERACTION PROBLEMS

In this paper, Damodar Maity (2003) discuss about the finite element analysis of

the fluid structure system by considering the couple effect of elastic structure of fluid.

The study was held to determine the condition of the dam structure. Due to the complex

11

topographical condition of dam structure, finite element method is recognized as one of

the powerful numerical tools in most practical problem (Maity, 2003)

Figure 2.7 Geometry and finite element discretization of dam

Source: Maity (2003)

Damodar Maity (2003), stated that at the top of the dam is made slightly thicker.

This is to prevent greater displacement at the top of the dam. Figure 2.7 shows the

thickness the top of the dam wall. This design could be used as one of the design for the

support structure of the flume. The concept of the dam could be used to adapt at the

flume. This will enhance the support structure of the flume hence, more design could be

proposed. Even though the M. Ghazavi (2003) did not consider the displacement at the

top of the sidewall, new design could be develop to compare with the design

recommended by M. Ghazavi.

2.6 DESIGN CONSIDERATION FOR COUNTERFORT WALL

There are various designs of the counterfort wall design. Some were suggesting

building the support structure along the flume. This type is known as mass concrete and

12

the material used are concrete. Mass concrete could be used as the support structure of

the flume. In term of effectiveness of the support structure, mass concrete would give a

similar result to the counterfort wall design. In 1908, John Monash proved that a

significant financial saving could be achieved overall.

Figure 2.8: Mass concrete

Source: www.vicnet.net.au

Mass concrete also shown that it would require high volume compared to

counterfort wall. Therefore, volume of support structure was taken as consideration as it

will determine the cost building the support structure. Other than the volume of the

support structure, the design from M. Ghazavi will be compared with the new design by

changing the parameters of the breadth of support structure, the amount support structure

and the length the support structure. Different design will give different result on the

displacement of the sidewall of the flume.

All the designs will be referring to the M. Ghazavi counterfort design in Table

2.1. The result of displacement due to changing parameter will be compared to Table 2.1

either the minimum and maximum parameter in M. Ghazavi (2003) is acceptable.

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